Infusion catheter

ABSTRACT

An infusion catheter system may deliver a therapeutic agent to a desired location in the body. The system may include an elongate catheter shaft having a proximal end region, a distal end region, a distal opening, and a lumen extending between the proximal end region and distal opening. The distal end region may include a coiled portion having a preformed coiled configuration including a plurality of helically wound rings. A plurality of apertures may be formed through a sidewall of the coiled portion. A guidewire may be configured to be slidably disposed within the lumen of the catheter shaft. The guidewire may include a proximal end region having a first cross-sectional dimension, an enlarged distal end region having a second cross sectional dimension greater than the first cross-sectional dimension, and an intermediate region disposed between the proximal end region and the distal end region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 62/347,942, filed Jun. 9, 2016, the entiredisclosure of which is herein incorporated by reference.

TECHNICAL FIELD

The disclosure is directed to accessory devices for use with catheters.More particularly, the disclosure is directed to devices to aid inremoving or accelerating the removal of clots.

BACKGROUND

A wide variety of intracorporeal medical devices have been developed formedical use, for example, intravascular use. Some of these devicesinclude guidewires, catheters, and the like. These devices aremanufactured by any one of a variety of different manufacturing methodsand may be used according to any one of a variety of methods. Of theknown medical devices and methods, each has certain advantages anddisadvantages. There is an ongoing need to provide alternative medicaldevices as well as alternative methods for manufacturing and usingmedical devices.

SUMMARY

This disclosure provides design, material, manufacturing method, and usealternatives for medical devices.

In a first example, an infusion catheter system may comprise an elongatecatheter shaft having a proximal end region, a distal end region, adistal opening, and a lumen extending between the proximal end regionand distal opening. The distal end region of the elongate catheter shaftmay include a coiled portion having a preformed coiled configurationincluding a plurality of helically wound rings. A plurality of aperturesmay be formed through a sidewall of the coiled portion and in fluidcommunication with the lumen of the catheter shaft. A guidewire may beconfigured to be slidably disposed within the lumen of the cathetershaft. The guidewire may include a proximal end region having a firstouter diameter, a distal end region having a second outer diameter, thesecond outer diameter greater than the first outer diameter, and anintermediate region disposed between the proximal end region and thedistal end region. The intermediate region may have a first flexibilitygreater than a second flexibility of the proximal end region.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may be formed at least in part of a shapememory material.

Alternatively or additionally to any of the examples above, in anotherexample, the distal end region of the guidewire may be configured to bedisposed in the distal opening of the catheter shaft during delivery ofa fluid through the lumen of the catheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may have a third flexibility less than thefirst flexibility and greater than the second flexibility.

Alternatively or additionally to any of the examples above, in anotherexample, the plurality of apertures may be formed in a radially outwardsidewall of the coiled portion.

Alternatively or additionally to any of the examples above, in anotherexample, when the coiled portion is disposed over the proximal endregion of the guidewire, the guidewire may bias the coiled portion fromthe preformed coiled configuration into a straight configuration.

Alternatively or additionally to any of the examples above, in anotherexample, when the coiled portion is disposed over the distal end regionof the guidewire, the tubular member may bias the guidewire into ahelical configuration.

Alternatively or additionally to any of the examples above, in anotherexample, the infusion catheter system may further comprise a fluiddelivery device fluidly coupled to the proximal end region of thecatheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may comprise a syringe.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may comprise an infusion pump.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may be configured to deliver atherapeutic drug to the lumen of the catheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may be configured to be biased into astraight configuration during delivery of the coiled portion to atreatment location and may be configured to recoil towards the preformedcoiled configuration when positioned adjacent to the treatment locationand a treatment is delivered.

Alternatively or additionally to any of the examples above, in anotherexample, the treatment location may be adjacent to a clot and thetreatment is delivery of a lytic.

Alternatively or additionally to any of the examples above, in anotherexample, delivery of the lytic may reduce a size of the clot and as thesize of the clot is reduced, the coiled portion may recoil towards thepreformed coiled configuration until the coiled portion returns to thepreformed coiled portion.

Alternatively or additionally to any of the examples above, in anotherexample, the plurality of apertures may be configured to maintaincontact with the clot while the coiled portion recoils towards thepreformed coiled configuration.

In another example, an infusion catheter system may comprise an elongatecatheter shaft having a proximal end region, a distal end region, adistal opening, and a lumen extending between the proximal end regionand distal opening. The distal end region may include a coiled portionhaving a preformed coiled configuration including a plurality ofhelically wound rings. A plurality of apertures may be formed through asidewall of the coiled portion and in fluid communication with the lumenof the catheter shaft. A guidewire may be configured to be slidablydisposed within the lumen of the catheter shaft. The guidewire mayinclude a proximal end region having a first outer diameter, a distalend region having a second outer diameter, the second outer diametergreater than the first outer diameter, and an intermediate regiondisposed between the proximal end region and the distal end region. Theintermediate region may have a first flexibility greater than a secondflexibility of the proximal end region.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may be formed at least in part of a shapememory material.

Alternatively or additionally to any of the examples above, in anotherexample, the distal end region of the guidewire may be configured to bedisposed in the distal opening of the catheter shaft during delivery ofa fluid through the lumen of the catheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may have a third flexibility less than thefirst flexibility and greater than the second flexibility.

Alternatively or additionally to any of the examples above, in anotherexample, the plurality of apertures may be formed in a radially outwardsidewall of the coiled portion.

Alternatively or additionally to any of the examples above, in anotherexample, when the coiled portion is disposed over the proximal endregion of the guidewire, the guidewire may bias the coiled portion fromthe preformed coiled configuration into a straight configuration.

Alternatively or additionally to any of the examples above, in anotherexample, when the coiled portion is disposed over the distal end regionof the guidewire, the tubular member may bias the guidewire into ahelical configuration.

Alternatively or additionally to any of the examples above, in anotherexample, the infusion catheter system may further comprise a fluiddelivery device fluidly coupled to the proximal end region of thecatheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may comprise a syringe.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may comprise an infusion pump.

Alternatively or additionally to any of the examples above, in anotherexample, the fluid delivery device may be configured to deliver atherapeutic drug to the lumen of the catheter shaft.

In another example, an infusion catheter system may comprise an elongatecatheter shaft having a proximal end region, a distal end region, adistal opening, and a lumen extending between the proximal end regionand distal opening. The distal end region may include a coiled portionformed at least in part from a shape memory material and having apreformed coiled configuration including a plurality of helically woundrings. A plurality of apertures may be formed through a sidewall of thecoiled portion such that the plurality of apertures are oriented in aradially outward direction when the coiled portion is in the preformedcoiled configuration. The plurality of apertures may be in fluidcommunication with the lumen of the catheter shaft. A fluid deliverydevice may be fluidly coupled to the proximal end region of the cathetershaft. A guidewire may be configured to be slidably disposed within thelumen of the catheter shaft. The guidewire may include a proximal endregion having a first outer diameter, a distal end region having asecond outer diameter, the second outer diameter greater than the firstouter diameter, and an intermediate region disposed between the proximalend region and the distal end region. The intermediate region may have afirst flexibility greater than a second flexibility of the proximal endregion.

Alternatively or additionally to any of the examples above, in anotherexample, the distal end region of the guidewire may be configured to bedisposed in the distal opening of the catheter shaft during delivery ofa fluid through the lumen of the catheter shaft.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may be configured to be biased into astraight configuration during delivery of the coiled portion to atreatment location and configured to recoil towards the preformed coiledconfiguration when placed adjacent to the treatment location and atreatment is delivered.

Alternatively or additionally to any of the examples above, in anotherexample, the plurality of apertures may be configured maintain contactwith the treatment location while the coiled portion recoils towards thepreformed coiled configuration.

An example method of reducing a size of a thrombus in a vessel maycomprise advancing a guidewire through a patient's vasculature to afirst location. The guidewire may comprise a proximal end region, anintermediate region, and a distal end region. The method may furthercomprise advancing an infusion catheter over the guidewire. The infusioncatheter may comprises an elongate catheter shaft having a proximal endregion, a distal end region, a distal opening, and a lumen extendingbetween the proximal end region and distal opening. The distal endregion may include a coiled portion having a preformed coiledconfiguration including a plurality of helically wound rings and aplurality of apertures formed through a sidewall of the coiled portionand in fluid communication with the lumen of the catheter shaft. Themethod may further comprise retracting the guidewire through thepatient's vasculature to a second location proximal to the firstlocation and adjacent to the thrombus. Retracting the guidewire to thesecond location may bring the plurality of apertures into contact withthe thrombus. The method may further comprise positioning the distal endregion of the guidewire in the distal opening of the catheter shaft andadministering a therapeutic drug through the lumen of the cathetershaft. The position of the distal end region of the guidewire may directthe therapeutic drug through the plurality of apertures.

Alternatively or additionally to any of the examples above, in anotherexample, the coiled portion may be configured to be biased into astraight configuration during the step of advancing the infusioncatheter over the guidewire and configured to recoil towards thepreformed coiled configuration when the guidewire is retracted to thesecond location.

Alternatively or additionally to any of the examples above, in anotherexample, the therapeutic drug may be a lytic.

Alternatively or additionally to any of the examples above, in anotherexample, administering a therapeutic drug may reduce a size of thethrombus and as the size of the thrombus is reduced, the coiled portionmay recoil towards the preformed coiled configuration until the coiledportion returns to the preformed coiled portion.

Alternatively or additionally to any of the examples above, in anotherexample, the plurality of apertures may be configured to maintaincontact with the thrombus while the coiled portion recoils towards thepreformed coiled configuration.

The above summary of some example embodiments is not intended todescribe each disclosed embodiment or every implementation of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments in connection withthe accompanying drawings, in which:

FIG. 1 is a schematic view of an illustrative low pressure infusioncatheter system in a first configuration;

FIG. 2 is a side view of a distal portion of the illustrative cathetersystem of FIG. 1 in a second configuration; and

FIGS. 3-5 illustrate a side view of the distal portion of theillustrative catheter system of FIG. 1 in a lumen with a clot, as theclot is dissolved.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit aspects of the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION

All numeric values are herein assumed to be modified by the term“about”, whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may be indicative asincluding numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4,and 5).

Although some suitable dimensions ranges and/or values pertaining tovarious components, features and/or specifications are disclosed, one ofskill in the art, incited by the present disclosure, would understanddesired dimensions, ranges and/or values may deviate from thoseexpressly disclosed.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The detailed description and the drawings, which are notnecessarily to scale, depict illustrative embodiments and are notintended to limit the scope of the invention. The illustrativeembodiments depicted are intended only as exemplary. Selected featuresof any illustrative embodiment may be incorporated into an additionalembodiment unless clearly stated to the contrary.

Thrombectomy catheters and systems may be used to remove thrombus,plaques, lesions, clots, etc. from veins or arteries. These devices maybe effective to remove acute thrombus but may be less effective on olderor more organized thrombus, or areas of large clot burden such as thatseen in deep vein thrombosis (DVT). It may be desirable to provide aninfusion system that can keep the lytics in direct contact (or as closeas possible) with the clot as the clot is dissolved.

FIG. 1 is a schematic view of an illustrative low pressure infusioncatheter system 10 in a first configuration. The infusion cathetersystem 10 may be configured to deliver a fluid (e.g. a thrombolytic drugor therapeutic agent) through a plurality of holes or apertures 44 to avessel. In one example, the thrombolytic drugs delivered to the vesselinclude, but are not limited to, lytics (e.g., tissue plasminogenactivator (tPA)) or other drugs that interact with a thrombus andactively reduce the size (e.g. breakdown, dislodge, minimize oreliminate) the thrombus. In some examples, after the catheter system 10delivers the lytics or other drugs to actively reduce the size of thethrombus, a thrombectomy catheter may be used to further macerate andaspirate any remaining thrombus within the vessel. For example, oncecatheter system 10 has treated the thrombus with the lytics or otherdrugs, the thrombectomy catheter is used to clear any remainingthrombus. In an example, using the catheter system 10 in combinationwith a thrombectomy catheter can reduce the overall procedure time.Examples of thrombectomy catheters are described in Bonnette et al.,U.S. Patent Publication No. 2006/0129091, entitled “ENHANCED CROSSSTREAM MECHANICAL THROMBECTOMY CATHETER WITH BACKLOADING MANIFOLD,”Bonnette et al., U.S. Pat. No.: 6,676,637, entitled “SINGLE OPERATOREXCHANGE FLUID JET THROMBECTOMY METHOD,” and Bonnette et al., U.S. Pat.No.: 6,945,951, entitled “THROMBECTOMY CATHETER AND SYSTEM,” which arehereby incorporated herein by reference in their entirety.

The illustrative infusion catheter system 10 may include a catheter 11and a manifold assembly 12. The catheter 11 may include an elongatecatheter shaft 18 extending from a proximal end region 14 to a distalend region 24. A lumen 19 may extend from the proximal end region 14 tothe distal end region 24 of the catheter shaft 18. The distal end region24 may include a coiled or helical portion 20 configured to deliver athrombolytic drug or other fluid to a vessel through the plurality ofapertures 44. A strain relief fitting 16 may be coupled to the manifoldassembly 12 and the proximal end region 14 of the catheter shaft 18. Insome embodiments, the proximal end region 14 may extend through a lumenof strain relief fitting 16.

A fluid delivery device 38 may be coupled through a tube 36, or othermeans (e.g. a needle), to manifold assembly 12 at a side port 34 of themanifold assembly 12. The side port 34 may be in fluid communicationwith the lumen 19 of the catheter shaft 18 such that the fluid deliverydevice 38 is fluidly coupled to the catheter shaft to deliver fluid 42through the apertures 44 in the coiled portion 20 and to a vessel. Insome embodiments, the fluid delivery device 38 may be a drug infusionpump or injector. In other embodiments, the fluid delivery device 38 maybe syringe. The fluid delivery device 38 may pump a volume of a fluid 42from a fluid reservoir 40, if so provided, into the lumen 19 to generatea pressurized source of fluid within the lumen 19. In an example, thefluid 42 may include thrombolytic drugs such as lytics, and thepressurized source of fluid generates fluid jets when directed throughthe one or more apertures 44 of the coiled portion 20. In someinstances, the fluid 42 may be provided at pressures of 600 pounds persquare inch (psi) (4136 kilopascals (kPa)) or less, 500 psi (3447 kPa)or less, 400 psi (2758 kPa) or less, 250 psi (1724 kPa) or less, 100 psi(689 kPa) or less, as desired. In an example, the one or more apertures44 provide corresponding fluid jets at flow rates low enough to notcause appreciable hemolysis. Some example fluid delivery devices 38 aredescribed in Cowan et al., U.S. Pat. No. 7,666,169, entitled “SYRINGEAND SYRINGE PLUNGERS FOR USE WITH MEDICAL INJECTORS” and Critchlow etal., U.S. Pat. No.: 6,520,930, entitled “INJECTORS, INJECTOR SYSTEMS ANDINJECTOR CONTROL”, which are hereby incorporated herein by reference intheir entirety. In some embodiments, a controller may be provided toallow for the automation and/or metering of the fluid delivery process.

The coiled portion 20 of the catheter shaft 18 may generally take theform of a helix including a plurality of windings or rings 22 a, 22 b,22 c, 22 d, 22 e (collectively 22). The size and spacing of the rings 22may be varied, as described herein. In some embodiments, the coiledportion 20 may comprise a polymeric tubular element attached (e.g. weld,melt, bond, etc.) to a distal portion of the catheter shaft 18.Alternatively, coiled portion 20 may be formed as a unitary structurewith the catheter shaft 18. In other embodiments, the coiled portion 20may be formed from a composite tubular element attached (e.g. weld,melt, bond, etc.) to the distal portion of the catheter shaft 18.

Some medical devices may be designed to have particular physicalcharacteristics such as flexibility (e.g., for the purposes of thisdisclosure, flexibility may be also be termed or expressed as bendingstiffness or flexural rigidity). For example, some medical devices maybe designed to be very stiff in order to provide enough columnarstrength to navigate anatomical areas of resistance. Alternatively, somemedical devices may be designed flexible enough in order to bend in amanner sufficient to traverse tortuous anatomy. Therefore, at the distalend of the medical device, it may be desirable to tailor the flexibilityof the medical device so that the device can effectively reach itstarget within the vasculature. It is contemplated that the cathetershaft 18 may be formed to have the desired flexibility and/or stiffnessto navigate the catheter shaft 18 to the desired treatment location.

The catheter shaft 18 may be formed in whole, or in part, from one ormore polymeric materials. In some instances, the catheter shaft 18 mayinclude an embedded reinforcement member, such as, but not limited, to abraid member or coil member. The reinforcement member may be formed froma polymer, metal, or composite material, as desired. Some illustrativematerials may include stainless steel or nitinol. It is contemplatedthat the coiled portion 20 may be formed in whole or in part from ashape memory material. The coiled portion 20 may be formed such that thehelical shape is the “remembered” or preformed shape. A biasing force(such as a guidewire 26) may bias the coiled portion 20 from itsremembered shape to a more linear, or straightened configuration. Oncethe biasing force is removed, the coiled portion 20 may return to itsremembered shape. In other embodiments, electroactive polymers may beused to form the coiled portion 20. The coiled portion 20 may then betransformed between configurations (e.g. coiled and substantiallystraight) when stimulated by an electric field.

The coiled portion 20 may generally take the form of a helix having aplurality of windings or connected rings 22. In some embodiments, thecoiled portion 20 may be formed by winding or wrapping a distal portionof the catheter shaft 18 around a mandrel and set in its “remembered”coiled shape. While the coiled portion 20 is illustrated as includingapproximately five rings 22, it is contemplated that the coiled portion20 may include any number of rings desired, such as, but not limited to,less than one, one, two, three, four, or more. A radiopaque marker 62may be positioned adjacent to the distal end region 24 of the cathetershaft 18. Additionally or alternatively, one or more radiopaque markersmay be positioned at any point along the length of the coiled portion 20and/or the catheter shaft 18 as desired.

The catheter 11 may transition from the generally straight cathetershaft 18 to the helically wound coiled portion 20 at a transition zoneor entry point 56 positioned adjacent to the proximal-most ring 22. Itis contemplated that the entry point 56 may be along a center line ofthe coiled portion 20. In other embodiments, the entry point 56 may beat the outer diameter of the rings 22, as shown in FIG. 1, or at pointbetween the center line of the coiled portion 20 and the outer diameterof the rings 22. In yet other embodiments, the entry point 56 may be apoint outside of the coiled portion 20.

While the rings 22 are illustrated as having substantially the sameouter diameter 71, the outer diameter of the rings 22 may be varied, asdesired. For example, the most proximal or most distal ring may have alarger outer diameter than then intermediate rings. This is just anexample. The rings 22 may have any combination of outer diameters 71desired. It is further contemplated that the pitch or the distancebetween one complete winding or ring, may vary or be the same betweenadjacent rings 22. A small pitch may result in a coiled portion 20 wherethe rings 22 are close to an adjacent ring 22 while a large pitch mayresult in a coiled portion 20 where the rings 22 are positioned furtherapart from adjacent rings 22.

In some embodiments, the apertures 44 may be formed in the coiledportion 20 after the coiled portion 20 has been formed. This may allowmost or all of the apertures 44 to be formed in region of the coiledportion 20 that would face a vessel wall when the catheter shaft 18 isdisposed within a vessel. In other words, the apertures 44 may be formedin a radially outward sidewall of the coiled portion 20 and/or orientedin a radially outward configuration. However, this is not required. Theapertures 44 may be formed at any time during the manufacturing processor at any position (e.g. an inner surface of the coiled portion 20, anouter surface of the coiled portion 20, between adjacent rings 22, etc.)along the coiled portion 20. The coiled portion 20 may include anynumber of apertures 44 desired, such as, but not limited to one or more,five or more, 10 or more, 20 or more, 50 or more, etc. In someembodiments, the apertures 44 may be formed at even intervals (e.g.evenly spaced) while in other embodiments, the apertures 44 may bepositioned at irregular intervals. In yet other embodiments, theapertures 44 may be positioned in groups or clusters. The one or moreapertures 44 may have a circular shape. In an example, the one or moreapertures 44 can have a number of different shapes. For example, the oneor more apertures 44 include, but are not limited to, circular, ovular,square, triangular, trapezoidal, polygonal, parallelogram, rhomboidal,and other irregular shapes, or combinations thereof. While notexplicitly shown, slits or flaps may be added to some or all of theapertures 44 to further control the flow of fluid 42. The apertures 44may have a diameter in the range of 0.005-0.015 inches (0.127-0.381 mm),in the range of 0.007-0.013 inches (0.178-0.330 mm), or about 0.010inches (0.254 mm).

In some embodiments, the guidewire 26 may include regions of varyingflexibility. For example, as shown in FIG. 2, a proximal end region 46of the guidewire 26 may be stiffer than (or less flexible than) anintermediate region 58 of the guidewire 26 and/or a distal end region 32of the guidewire 26. The proximal end region 46 may have a firststiffness that is greater than a second stiffness of the intermediateregion 58 and/or the distal end region 32. In other words, theintermediate region 58 and/or the distal end region 32 may have a firstflexibility that is greater than a second flexibility of the proximalend region 46. These are just examples. The guidewire 26 may include anynumber of regions each have differing flexibility. Alternatively, oradditionally, the guidewire 26 may have a constantly changingflexibility along a length thereof.

Referring to FIG. 2, which illustrates a portion of the coiled portion20 of FIG. 1 over a guidewire 26, the coiled portion 20 may be formedfrom a polymeric material having a third flexibility that is greaterthan the second flexibility of the proximal end region 46 and less thanthe first flexibility of the intermediate region 58 and/or the distalend region 32. As the stiffness of the proximal end region 46 of theguidewire 26 is greater than the stiffness of the coiled portion 20, theproximal end region 46 of the guidewire 26 may bias, hold, or otherwisedeform the coiled portion 20 from the preformed helical shape to agenerally straight configuration, as shown in FIG. 2. As the coiledportion 20 is slid or advanced distally along the guidewire 26, thecoiled portion 20 approaches the intermediate region 26. As the coiledportion 20 may be stiffer than the intermediate region and/or distal endregion 32 of the guidewire 26, the coiled portion 20 may return to itsremembered or preformed helical configuration.

For example, a guidewire 26 can be tracked into position and a catheter11 may be tracked over the guidewire. In other words, the guidewire 26and the catheter 11 may be slidably disposed relative to one another. Asthe coiled portion 20 of the catheter shaft 18 is tracked over thestiffer proximal end region 46 of the guidewire 26, the coiled portion20 of the catheter shaft 18 is straightened to allow for easieradvancement of the catheter shaft 18, as shown in FIG. 2. As the coiledportion 20 is tracked over the more flexible intermediate region 58 ofthe guidewire 26, the coiled portion 20 overcomes the bias of theguidewire 26 and returns to its generally helical shape, as shown inFIG. 1, while also biasing the guidewire 26 into a helicalconfiguration.

In some embodiments, the guidewire 26 may be provided with an enlargeddistal end region 32 having an atraumatic distal tip 30. The enlargeddistal end region 32 may be sized to have an outer diameter 70 similarin size to an inner diameter of the catheter shaft 18. In someembodiments, the enlarged distal end region 32 may be smaller than theinner diameter of the catheter shaft 18, substantially the same size asthe inner diameter of the catheter shaft 18, or larger than the innerdiameter of the catheter shaft 18, as desired. It is contemplated thatthe size and/or position of the enlarged distal end region 32 may beadjusted to adjust the flow rate of the fluid 42 exiting the apertures44. When fluid 42 is introduced into the lumen 19 of the catheter shaft18, the guidewire 26 may be positioned such that the enlarged distalregion is positioned within or just outside of the distal opening 60 ofthe catheter shaft 18. This may direct the fluid 42 towards and throughthe apertures 44 instead of the distal opening 60. It is contemplatedthat when fluid 42 is provided at a constant pressure and a largersurface area of the distal opening 60 is blocked, the fluid 42 will exitthe apertures 44 at a higher flow rate than when a smaller surface areaof distal opening 60 is blocked. It is contemplated that some fluid 42may exit through the distal opening 60.

In some embodiments, the catheter shaft 18 may have an inner diameter inthe range of 0.035-0.045 inches (0.889-1.143 millimeters (mm)), or about0.040 inches (1.016 mm). The enlarged distal end region 32 of theguidewire 26 may have an outer diameter in the range of 0.033-0.043inches (0.838-1.092 mm), or about 0.038 inches (0.965 mm) while theportion of the guidewire 26 proximal to the enlarged distal end region32 may have an outer diameter in the range of 0.021-0.031 inches(0.533-0.787 mm), or about 0.026 inches (0.660 mm). These are justexamples. It is contemplated that the catheter shaft 18 may be as smallas 4 French (Fr) or as large as 8 Fr, as desired. The guidewire 26and/or enlarged distal end region 32 may be sized according to the sizeof the catheter shaft 18. For example, a larger diameter catheter shaft18 may require a larger enlarged distal end region 32 of the guidewire26 and a smaller diameter catheter shaft 18 may require a smallerenlarged distal end region 32 of the guidewire 26. The guidewire 26 maytransition from a proximal outer diameter 72 to the enlarged distal endregion 32 at a transition zone 28. In some instances, the transitionzone 28 may be a tapered, or sloped region, while in other instance thetransition zone 28 may be an abrupt or step-wise transition. In someinstances, a gradual slope that occurs over a longer length (compared tosteep slope) may allow for the user to more particularly control thepercentage of the distal opening 60 blocked by the guidewire 26. Inother words, a gradual slope may allow the user to more particularlycontrol the flow rate of the fluid 42 exiting the apertures 44 bycontrolling the percentage of the distal opening 60 that is blocked bythe guidewire 26. While not explicitly shown, the guidewire 26 may beprovided with one or more radiopaque markers at any point along thelength of the guidewire 26. In one example, a radiopaque marker may beprovided adjacent to a transition in flexibility of the guidewire 26(e.g. between proximal end region 46 and intermediate region 58). Thismay allow a clinician to position the more flexible intermediate region58 adjacent to the clot or lesion to more precisely locate the coiledportion 20 of the catheter 11.

Additionally, or alternatively to the enlarged distal end region 32, theguidewire 26 and or the catheter shaft 18 may be provided with anexpandable balloon and/or other plug member configured to control theflow of fluid 42 from the distal opening 60. In some instances, theenlarged distal end region 32, balloon, or other plug member may be usedto mechanically control the recoiling of the coiled portion 20. Forexample, the enlarged distal end region 32, balloon, or other plugmember may be used to apply a proximal force on the distal end region 24of the catheter shaft 18 to cause the coiled portion 20 to recoil.

Use of the low pressure infusion catheter system 10 will now bedescribed with respect to FIGS. 3-5 which illustrate the coiled portion20 positioned in the lumen 50 of a vessel 48 of a patient and adjacentto a lesion, clot, plaque, thrombus, etc. 52. The guidewire 26 may beadvanced through the vasculature to a first location such that thedistal tip 30 is positioned distal to the clot 52 and/or theintermediate region 58 is positioned adjacent to the clot 52. Thecatheter 11 may then be advanced over the guidewire 26 towards the clot52. As described above, the stiff proximal end region 46 of theguidewire 26 may overcome the biasing force of the “remembered” coiledportion 20 such that the coiled portion 20 may be biased into a straightconfiguration to allow the catheter shaft 18 to be advanced in asubstantially straight configuration, as shown in FIG. 2. In someinstances, the distal tip 30 of the guidewire may be advanced asufficient distance past the clot 52 to allow the coiled portion 20 tobe positioned adjacent to the clot 52 in a generally straightconfiguration, although this is not required. Once the coiled portion 20has been positioned adjacent to the clot 52, the guidewire 26 may beproximally retracted to a second location until the stiff proximal endregion 46 is located proximal of the coiled portion 20. For clarity,only a portion of the guidewire 26 that is disposed within the lumen 19of the catheter shaft 18 has been illustrated in phantom. It should beunderstood that the guidewire 26 is positioned within coiled portion 20even when the coiled portion 20 begins to assume its remembered state.

As the guidewire 26 is proximally retracted to the second location, thecoiled portion 20 may begin to contract in length along direction 64while radially expanding (e.g. the coiled portion 20 recoils) bringingthe coiled portion 20 and/or the plurality of apertures 44 into contactwith the clot. As shown in FIGS. 3 and 4, the clot 52 may block aportion of the vessel lumen 50 such that all or a portion of the coiledportion 20 may not fully return to its remembered state. In such aninstance, the coiled portion 20 may contract in length and radiallyexpand until an outer surface contacts the clot 52 thus bringing thecoiled portion 20 into intimate contact with the clot 52. In someinstances, the clot 52 may be of a size such that the coiled portion 20cannot appreciably recoil when it is deployed. As can be seen in FIG. 3,the pitch D1 of the rings 22 where the coiled portion 20 cannot fullyreturn to its remembered state may be greater than the pitch D3 of therings 22 when the coiled portion 20 fully returns to its rememberedstate (see FIG. 5). Once the coiled portion 20 has been positioned tothe user's satisfaction, the guidewire 26 can be proximally retracted tobring the enlarged distal end region 32 into the distal opening 60 ofthe catheter shaft 18, if it is not already there.

The fluid delivery device 38 may then be used to deliver or administer aflow of fluid 42 through the lumen 19 of the catheter shaft 18. Thefluid 42 may exit the catheter shaft 18 through the apertures 44 formedin the sidewall of the coiled portion 20. For example, the position ofthe distal end region 32 may direct the fluid 42 radially outwardsthrough the plurality of apertures 44. The fluid 42 (e.g., athrombolytic fluid) may impact and penetrate the clot 52 adjacent to theapertures 44 and actively reduce the size (e.g., break down) andminimize or eliminate the clot 52. In some embodiments, the fluid 42 mayweep or drip from the apertures 44 while in other instances, the fluid42 may spray with more force than a drip. As the clot 52 size isreduced, the coiled portion 20 may continue to contract in length alongdirection 64 while radially expanding, as shown in FIG. 4. As can beseen in FIG. 4, a pitch D2 of the rings 22 is where the coiled portion20 has not fully return to its remembered state and, as such, is smallerthan the pitch D1 prior to beginning treatment. FIG. 5 illustrates therings fully returned to an original pitch D3, which, is smaller thanpitch D1 and D2. As the clot 52 continues to shrink in size, the coiledportion 20 may continually contract in length along direction 64 whileradially expanding. This may help maintain intimate contact between thecoiled portion 20 and the clot 52 during delivery of the fluid 42. It iscontemplated that the apertures 44 may be positioned such that theapertures 44 maintain contact with (e.g. are directed towards the vessel48 wall) of the coiled portion 20 as it recoils.

The fluid delivery device 38 may continue to deliver fluid 42 until theclot 52 has been reduced to a desired size, it has been determined thatthe fluid 42 is no longer reducing the size of the clot 52 and/or thecoiled portion 20 has returned to its original “remembered” configured,as shown in FIGS. 1 and 5. To remove the catheter shaft 18 from thevessel 48, the guidewire 26 may be advanced distally until the stiffproximal end region 46 of the guidewire 26 is disposed within the coiledportion 20 and biases the coiled portion 20 to a substantially straightconfiguration, as shown in FIG. 2, to facilitate removal of the catheter11. It is contemplated that the guidewire 26 may also be used tostraighten the coiled portion 20 to facilitate relocation of the coiledportion 20, if necessary. The catheter shaft 18 may be proximallyretracted from the body prior to removing the guidewire 26, orsimultaneously with the guidewire 26, as desired. In some embodiments,the guidewire may be left in place to facilitate further treatment withother devices, such as but not limited to a thrombectomy catheter.

The materials that can be used for the various components of thecatheter, guidewires, accessory device, and/or other devices disclosedherein may include those commonly associated with medical devices. Forsimplicity purposes, the following discussion makes reference toaccessory devices and their related components. However, this is notintended to limit the devices and methods described herein, as thediscussion may be applied to other similar devices, tubular membersand/or components of tubular members or devices disclosed herein.

The various components of the devices/systems disclosed herein mayinclude a metal, metal alloy, polymer (some examples of which aredisclosed below), a metal-polymer composite, ceramics, combinationsthereof, and the like, or other suitable material. Some examples ofsuitable metals and metal alloys include stainless steel, such as 304V,304L, and 316LV stainless steel; mild steel; nickel-titanium alloy suchas linear-elastic and/or super-elastic nitinol; other nickel alloys suchas nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL®625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such asHASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copperalloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS®400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g.,UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys,other nickel-molybdenum alloys, other nickel-cobalt alloys, othernickel-iron alloys, other nickel-copper alloys, other nickel-tungsten ortungsten alloys, and the like; cobalt-chromium alloys;cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®,PHYNOX®, and the like); platinum enriched stainless steel; titanium;combinations thereof; and the like; or any other suitable material.

Some examples of suitable polymers may include polytetrafluoroethylene(PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylenepropylene (FEP), polyoxymethylene (POM, for example, DELRIN® availablefrom DuPont), polyether block ester, polyurethane (for example,Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC),polyether-ester (for example, ARNITEL® available from DSM EngineeringPlastics), ether or ester based copolymers (for example,butylene/poly(alkylene ether) phthalate and/or other polyesterelastomers such as HYTREL® available from DuPont), polyamide (forexample, DURETHAN® available from Bayer or CRISTAMID® available from ElfAtochem), elastomeric polyamides, block polyamide/ethers, polyetherblock amide (PEBA, for example available under the trade name PEBAX®),ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE),Marlex high-density polyethylene, Marlex low-density polyethylene,linear low density polyethylene (for example REXELL®), polyester,polybutylene terephthalate (PBT), polyethylene terephthalate (PET),polytrimethylene terephthalate, polyethylene naphthalate (PEN),polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI),polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (for example, KEVLAR®), polysulfone,nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon),perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin,polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS A),polycarbonates, ionomers, biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like. In some embodiments the sheath can be blendedwith a liquid crystal polymer (LCP). For example, the mixture cancontain up to about 6 percent LCP.

In at least some embodiments, portions or all of the accessory devicesand their related components may be doped with, made of, or otherwiseinclude a radiopaque material. Radiopaque materials are understood to bematerials capable of producing a relatively bright image on afluoroscopy screen or another imaging technique during a medicalprocedure. This relatively bright image aids the user of the accessorydevices and their related components in determining its location. Someexamples of radiopaque materials can include, but are not limited to,gold, platinum, palladium, tantalum, tungsten alloy, polymer materialloaded with a radiopaque filler, and the like. Additionally, otherradiopaque marker bands and/or coils may also be incorporated into thedesign of the accessory devices and their related components to achievethe same result.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of thedisclosure. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. An infusion catheter system, comprising: anelongate catheter shaft having a proximal end region, a distal endregion, a distal opening, and a lumen extending between the proximal endregion and distal opening, wherein the distal end region includes acoiled portion having a preformed coiled configuration including aplurality of helically wound rings; a plurality of apertures formedthrough a sidewall of the coiled portion and in fluid communication withthe lumen of the catheter shaft; and a guidewire configured to beslidably disposed within the lumen of the catheter shaft, the guidewireincluding a proximal end region having a first outer diameter, a distalend region having a second outer diameter, the second outer diametergreater than the first outer diameter, and an intermediate regiondisposed between the proximal end region and the distal end region;wherein the intermediate region has a first flexibility greater than asecond flexibility of the proximal end region.
 2. The infusion cathetersystem of claim 1, wherein the coiled portion is formed at least in partof a shape memory material.
 3. The infusion catheter system of claim 1,wherein the distal end region of the guidewire is configured to bedisposed in the distal opening of the catheter shaft during delivery ofa fluid through the lumen of the catheter shaft.
 4. The infusioncatheter system of claim 1, wherein the coiled portion has a thirdflexibility less than the first flexibility and greater than the secondflexibility.
 5. The infusion catheter system of claim 1, wherein theplurality of apertures are formed in a radially outward sidewall of thecoiled portion.
 6. The infusion catheter system of claim 1, wherein whenthe coiled portion is disposed over the proximal end region of theguidewire, the guidewire biases the coiled portion from the preformedcoiled configuration into a straight configuration.
 7. The infusioncatheter system of claim 1, wherein when the coiled portion is disposedover the distal end region of the guidewire, the tubular member biasesthe guidewire into a helical configuration.
 8. The infusion cathetersystem of claim 1, further comprising a fluid delivery device fluidlycoupled to the proximal end region of the catheter shaft.
 9. Theinfusion catheter system of claim 8, wherein the fluid delivery devicecomprises a syringe.
 10. The infusion catheter system of claim 8,wherein the fluid delivery device comprises an infusion pump.
 11. Theinfusion catheter system of claim 8, wherein the fluid delivery deviceis configured to deliver a therapeutic drug to the lumen of the cathetershaft.
 12. An infusion catheter system, comprising: an elongate cathetershaft having a proximal end region, a distal end region, a distalopening, and a lumen extending between the proximal end region anddistal opening, wherein the distal end region includes a coiled portionformed at least in part from a shape memory material and having apreformed coiled configuration including a plurality of helically woundrings; a plurality of apertures formed through a sidewall of the coiledportion such that the plurality of apertures are oriented in a radiallyoutward direction when the coiled portion is in the preformed coiledconfiguration, the plurality of apertures in fluid communication withthe lumen of the catheter shaft; a fluid delivery device fluidly coupledto the proximal end region of the catheter shaft; and a guidewireconfigured to be slidably disposed within the lumen of the cathetershaft, the guidewire including a proximal end region having a firstouter diameter, a distal end region having a second outer diameter, thesecond outer diameter greater than the first outer diameter, and anintermediate region disposed between the proximal end region and thedistal end region; wherein the intermediate region has a firstflexibility greater than a second flexibility of the proximal endregion.
 13. The infusion catheter system of claim 12, wherein the distalend region of the guidewire is configured to be disposed in the distalopening of the catheter shaft during delivery of a fluid through thelumen of the catheter shaft.
 14. The infusion catheter system of claim12, wherein the coiled portion is configured to be biased into astraight configuration during delivery of the coiled portion to atreatment location and configured to recoil towards the preformed coiledconfiguration when placed adjacent to the treatment location and atreatment is delivered.
 15. The infusion catheter system of claim 14,wherein the plurality of apertures are configured maintain contact withthe treatment location while the coiled portion recoils towards thepreformed coiled configuration.
 16. A method of reducing a size of athrombus in a vessel, the method comprising: advancing a guidewirethrough a patient's vasculature to a first location, the guidewirecomprising a proximal end region, an intermediate region, and a distalend region; advancing an infusion catheter over the guidewire, theinfusion catheter comprising: an elongate catheter shaft having aproximal end region, a distal end region, a distal opening, and a lumenextending between the proximal end region and distal opening, whereinthe distal end region includes a coiled portion having a preformedcoiled configuration including a plurality of helically wound rings; anda plurality of apertures formed through a sidewall of the coiled portionand in fluid communication with the lumen of the catheter shaft;retracting the guidewire through the patient's vasculature to a secondlocation proximal to the first location and adjacent to the thrombus,wherein retracting the guidewire to the second location brings theplurality of apertures into contact with the thrombus; positioning thedistal end region of the guidewire in the distal opening of the cathetershaft; and administering a therapeutic drug through the lumen of thecatheter shaft, wherein the position of the distal end region of theguidewire directs the therapeutic drug through the plurality ofapertures.
 17. The method of claim 16, wherein the coiled portion isconfigured to be biased into a straight configuration during the step ofadvancing the infusion catheter over the guidewire and configured torecoil towards the preformed coiled configuration when the guidewire isretracted to the second location.
 18. The method of claim 17, whereinthe therapeutic drug is a lytic.
 19. The method of claim 18, whereinadministering a therapeutic drug reduces a size of the thrombus and asthe size of the thrombus is reduced, the coiled portion recoils towardsthe preformed coiled configuration until the coiled portion returns tothe preformed coiled portion.
 20. The method of claim 19, wherein theplurality of apertures are configured to maintain contact with thethrombus while the coiled portion recoils towards the preformed coiledconfiguration.